1. Field of the Invention
The present invention relates to a set of cartridges having different capacities and a printer comprising the set of cartridges and a printer main body.
2. Description of Related Art
A known ink-jet printer, such as a printer described in JP-A-2005-246781, has a printer main body and cartridges having tanks for storing ink, and the cartridges are configured to be mounted to the printer main body. The printer is configured to form images on a sheet of paper with ink supplied from the cartridges. The printer has an ink amount detection mechanism for detecting an amount of ink stored in the cartridge. The printer is configured to notify a user when the amount of ink becomes little.
The cartridge has a shutter mechanism having a light-blocking panel configured to move up and down based on the change of ink level in the tank. The printer main body has an optical sensor having a light-emitting portion and a light-receiving portion at a predetermined position. When the amount of ink stored in the tank of the cartridge is large, the light-blocking panel is positioned between the light-emitting portion and the light-receiving portion and an optical signal emitted from the light-emitting portion toward the light-receiving portion is blocked by the light-blocking panel. In contrast, when the amount of ink stored in the tank is reduced and the ink level is lowered to a predetermined height, the light-blocking pane moves out of a space between the light-emitting portion and the light-receiving portion, such that the optical signal emitted from the light-emitting portion reaches the light-receiving portion. Therefore, the fact that the amount of ink is reduced to a predetermined amount, i.e., a near-empty state of the tank, can be detected by the light-receiving portion receiving the optical signal emitted from the light-emitting portion.
The amount of ink stored in the tank after the near-empty state of the tank is detected is estimated by a controller in the printer main body performing a “soft count” of an amount of used ink (an amount of ink discharged from an ink-jet head), i.e., by the controller counting the amount of ink discharged from the ink-jet head with a software. Accordingly, the printer can encourage a user to replace the cartridge with a new one before the amount of ink stored in the tank becomes completely zero.
An amount of ink consumption of the printer is different between a printer for home use and a printer for business use. Therefore, a printer which allows selective use of cartridges different in ink-storage capacity is desired. To meet this demand, the known printer, such as a printer described in JP-A-2005-246781, has a small-capacity cartridge and a large-capacity cartridge which can be selectively mounted to a holder of the printer main body. The above-described shutter mechanisms of the respective cartridges having different capacities have the same structure.
Because the shutter mechanisms of the cartridges having different capacities have the same structure, the near-empty state of the tank is detected when the ink level in the each tank reaches the same predetermined level irrespective of the difference in capacity of the cartridge. In this case, because of the difference in capacity among the respective cartridges, i.e., the difference in shape and size of the tank, the amount of ink when the tank in the large-capacity cartridge is detected to be in the near-empty state is greater than the amount of ink when the tank in the small-capacity cartridge is detected to be in the near-empty state. If the amount of ink is large when the tank is detected to be in the near-empty state, an error in the estimation of the amount of ink by the subsequent soft count becomes disadvantageously large.